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Study of antioxidants in dried fruits.
Barošová, Michaela ; Drábková,, Michaela (referee) ; Márová, Ivana (advisor)
Presented diploma work is focused on study of antioxidants in different kinds of dried fruits. Analyses of ascorbate, tocopherols, carotenoids and flavonoids were performed using RP-HPLC with spectrophotometric detection. Analysis of dried fruits showed high level of vitamins and phenolocs mainly in berries. High level of carotenoids was observed in dried apricots and plums. Further, antioxidant activity of dried fruit extracts was tested by ABTS method. High antioxidant activity was found mainly in dried apples, cranberries and blueberries. The biological test with yeast Sascharomyces cerevisiae D7 was used for the analysis of antimutagenic efects of dried fruits. High antimutagenic activity exhibited dried cranberries and blueberries. Most of tested dried fruits with high antimutagenic effect exhibited also high antioxidant activity as well as high content of some antioxidants. No direct correlation was found among these parameters. Last part of this work was focused on study of influence of drying on antioxidant content in two types of apples. Drying at mild controlled conditions exhibited no significant negative effect on active substance content; in some samples their concentration was observed.
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Antioxidative substances in selected fruit and herbal teas
Tomková, Martina ; Buňková, Radka (referee) ; Márová, Ivana (advisor)
This diploma project deals with antioxidant and antimutagenic properties of selected herbal and fruit teas commonly used in Czech population. Influence of different tea packaging (bag teas and loose leaf teas) on bioactive compound content was compared. Further, effect of long-term storage in common household conditions was studied. Antioxidant properties of teas were characterized using some group parameters - total antioxidant activity ("Randox Total Antioxidant Status Kit"), total phenolics and total flavonoids - as well as some individual representatives of low molecular weight antioxidants. Higher antixidant content was found in herbal teas than in fruit teas. Comparing bag teas with loose leaf teas higher antioxidant activity was shown in loose leaf teas. Individual antioxidants were analyzed using HPLC method with spectrophotometric detection and verified by on-line LC/MS. IN all tea samples catechins - catechin, epicatechin, epicatechin gallate and other flavonoids - rutin, morin, quercetin, kaempferol, myricetin and luteolin were determined. In most of teas high level of catechin and rutin was detected. The highest level of flavonoids was determined in herbal poured teas. Ascorbic acid content was also determined by HPLC method. Higher vitamine C level was found in most of fruit teas and in rose hip tea. Antimutagenicity of tea extracts was tested by in vitro test using Saccharomyces cerevisiae D7 yeast. High antimutagenic activity showed mainly nettle tea, tutsan tea and most of fruit teas. During long-term storage (1 year, 20°C, darkness) a significant decrease of all analyzed antioxidant parameters was followed. Higher lost of antioxidants was found in fruit teas when compared with the herbal ones.
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In vitro study of antioxidant activity of food supplements
Vopelková, Dominika ; Pořízka, Jaromír (referee) ; Omelka, Ladislav (advisor)
Bachelor thesis deals with the determination of antioxidant activity of food supplements in vitro. The theoretical part focuses on legislative requirements of food supplements, their characteristic and classification. Further, the attention is also devoted to antioxidants, their properties, effects, importance and utilization. Separate chapter describes herbs, which are an essential component of researched supplements, their effects and properties. For experimental part several food supplements in various forms (capsule, tea, juice, dried fruits) were chosen and total content of polyphenols was determined using the UV-VIS spectroscopy. Further, the total antioxidant activity is characterized by electron paramagnetic resonance involving DPPH method.
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Changes of antioxidants in selected fruits during long-term freezing
Štindlová, Jitka ; Lichnová, Andrea (referee) ; Márová, Ivana (advisor)
In this bachelor thesis some low molecular weight antioxidants contained in strawberries, raspberries, blueberries and cranberries are described. In the theoretical part also general characteristics of these fruits are introduced. Experimental part was focused on analysis of the changes of selected antioxidant content in the fruits. These changes were monitored during storage in two different conditions – in refrigerator and in freezer. In refrigerator whole fruits were stored for 8 days. The experiment in the freezer was performed for 2 months and the fruits were stored in four different processed forms – as a whole fruit, whole fruit impregnated by sucrose solution, as a pulp and pulp mixed with sucrose. Antioxidant content in fruits was analyzed by HPLC and spectrophotometry. The highest total content of antioxidants was found in strawberries, while the lowest values were found in raspberries. During storage some part of original antioxidant content stayed conserved, the highest content was preserved in blueberries processed as a whole fruits and impregnated whole fruits.
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Analysis of phenolics in different kinds of coffee
Jašková, Martina ; Halienová, Andrea (referee) ; Márová, Ivana (advisor)
The aim of this bachelor thesis was examining the quantity of biologically significant substances in selected types of roasted ground coffee, instant coffee and coffee extract. The particular kinds of coffee differed in technological processing, degree of roasting and composition. In the practical part total phenolics and flavonoids by using spectrophotometry methods. The total antioxidant activity in the individual coffee extracts was determined by ABTS method. Qualitative and quantitative analysis of some individual antioxidants and caffeine was performed using RP-HLPC with spectrophotometric detection. As a part of the work sensory analysis of all coffee samples was realized and consumer questionnaires were completed.
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Analysis of biologically active substances in some cereal products
Valentová, Radka ; Starečková, Terezie (referee) ; Márová, Ivana (advisor)
Presented bachelor thesis is focused on study of biologically active substances in cereal products. In theoretical part over view of cereal active substances, predominantly phenolic compounds were introduced. In practical part 15 kinds of cereal products were analyzed. In these materials some group parameters - total phenolics, total flavonoids and total antioxidant activity were measured by spectrophotometry. RP-HPLC/UV-VIS method was performed for analysis of selected individual flavonids. The highest content of phenolic compounds was measured in cereals containing fruits (raspberries, blueberries, tropical and red fruit), cacao, crusty fruits (hazel nuts, sunflower seeds) and buckwheat. All cereal products contain catechine, epicatechine, catechin gallate, epicatechin gallate, chlorogenic and ferulic acid. As a part of bachelor thesis simple sensory analysis was performed and consumer questionnaires were evaluated.
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Biologically significant substances in cereal products
Vondráčková, Hedvika ; Halienová, Andrea (referee) ; Márová, Ivana (advisor)
Presented work was focused on study of biologically significant substances in cereal products. In experimental part selected active substances in cereal bars were analyzed. The highest content of total phenolics, total flavonoids, total antioxidant capacity, procyanidin B2 and chlorogenic acid was measured in plums and blueberry bars. The highest level of reduced saccharides was evaluated in raspberry and cereal bars. Presence of main simple sugars - maltose, glucose and fructose was detected in all bar samples.
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Vplyv fortifikácie v rôznych štádiách macerácie/fermentácie na antioxidačné vlastnosti vín
Holovic, Michal
Diploma thesis dealt with studying and evaluating the impact of fortification in different stages of maceration/fermentation on antioxidant properties of wine. The literary part of the work was clearly described chapters on various production methods and types of fortified wines, different classes of phenolic substances present in wine and study of antioxidant activity of wine and methods of assessment. In the practical part, were selected three blue grape variety from which it was successively produced 9 samples fortified wines. Time fortification took place in three different stages of maceration. The first was the fortification to the must before the start of fermentation, a second fortification during the fermentation of sugar - fermentation to about 7 % by volume alcohol, and the third fortification after fermentation in young dry wine. Fortification was carried out by adding the calculated amount of spirit in the volume of wine or must, at the same level of spirituosity all the resulting wine samples. After some time joining the distillate was carried out basic analysis of wine samples and determination of the profile of phenolic compounds. Spectrophotometric method was further assessed total content of phenolic compounds, flavanols, anthocyanins and antioxidant activity, which was determined by two different methods. Basic analysis and spectrophotometric measurements were performed in triplicate and the results were averaged. Samples of fortified wines were finally sensory evaluated participation of 12 tasters, and all the results summarized in tables and graphs, statistically evaluated and described in drawing conclusions for practical use.
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Studium antioxidačních látek u hroznových semen
Tomášková, Lenka
It is known, that grape seeds are rich in significant antioxidant. The issue of dealing with the analysis and comparison of antioxidant components in the seeds of Vitis vinifera in the individual varieties has not been sufficiently studied, yet. In the first part of the thesis is an extensive literature focused on a summary of the work, which study substances in the vine seeds and their effect on human health. Experimental work is focused on the study of antioxidant components in the seeds of Vitis vinifera. The experiment was used extracts of the three "normal" (Frankova, Ryzlink vlašský and Cabernet Moravia) and three interspecific varieties (Nativa, Marlen and Kofranka). Spectrometric, using three fundamentally different methods - DPPH, ABTS and FRAP was determined antioxidant activity . Spectrophotometry was further investigated the content of total polyphenolic compounds and total content of flavanols . Technique of high- performance liquid chromatography with mass spectroscopy were analyzed nine major flavonoids (apigenin, astragalin, hyperoside, isorhamnetin, kaempferol, myricetin, quercetin, quercitrin and rutin) and two procyanidins (procyanidin A2 and procyanidin B1). The highest values of antioxidant reached interspecific varieties Marlen and Nativa, at the least antioxidant components were recorded in the variety Cabernet Moravia. However, in complex evaluation, between studied of varieties were not significant differences.
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Obohacené nápoje na bázi vína
Deutscharová, Jitka
This thesis was prepared at the Institute of Post-Harvest Technologies of Horticulture at the Faculty of Horticulture of the Mendel University in Brno in years 2012/2014. The aim of this thesis was to elaborate on the nutritional constitution of wines with emphasis on phenolic components, to deal with methods of determination of the antioxidant activity and to compile the legislative requirements relevant to selected wines. In the experimental part, wine-based beverages with the addition of wood chips or their extracts were designed and prepared. Subsequently, selected quality parameters of the prepared beverages were compared and the prospects of their success in the market place were evaluated.
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